Abstract: The seismic deformation zone of M 7.6 Lancang earthquake in 1988 is mainly composed of a series of surface ruptures and distributed along the Muga and Datangzi faults, The mechanical property of right-lateral shear of the deformation zone is analysed. But some segments of the zone exhibit their left-lateral shearing movement.Based on the field investigation and comprehensive analysis of data, it is considered that the axis of principal stress for the event is in NS-NNE direction. The seismic faulting of the event should represent a right-lateral displacement. The ground cracks which exhibit left-lateral displacement were formed by right-lateral displacement of faults.

Key words: Yunnan, Lanchang earthquake, Fault, Deformation zone, Groud fisssure

摘要： 澜沧7.6级地震形变带主要以地震裂缝带的形式出现,未发现有类似耿马7.2级地震的地震断层。裂缝主要沿木戛断裂带和大塘子断裂带分布,构造地裂缝的性质有左旋和右旋。对构造地裂缝实测资料及现场的综合分析认为:澜沧7.6级地震的主压应力方向应为近南北向至北北东向,地震时断层活动主要以右旋为主,左旋地裂缝是在断层突发性的右旋错动下的产物。

关键词: 云南, 澜沧地震, 断裂, 地震形变带, 地裂缝